About TB

Tuberculosis (TB) is caused by bacteria, Mycobacterium tuberculosis, and usually attacks your lungs. It used to be rare in developed countries, but since 1985 TB cases have been on the rise. Partly this is due to HIV/AIDS, which weakens your immune system and makes it harder to fight off TB. [Microscopic view of TB (rods) shown at right.]

TB is contagious and spreads through the air. When people with TB cough, sneeze, talk, spit, or even sing they launch TB bacteria into the air. Inhaling just a few of these TB germs can lead to infection. If a person who has TB isn't treated, they can infect as many as 10 to 15 people on average per year. Even if the infected people don't become sick right away TB can come back to haunt them years later (especially if they have a weakened immune system). According to the World Health Organization, as of 2010 one-third of the world's population is currently infected with TB. Of those who don't have HIV, 5 to 10% become sick or infectious at some time during their lives. For people with HIV, the TB infection rate is much higher.

The signs and symptoms of active TB often include cough, weight loss, fatigue, fever, night sweats, chills, and loss of appetite. A simple skin test for TB is the most commonly used test, although sometimes blood tests are used too. TB that isn't treated properly can be fatal.

The good news is drugs can treat it, but the bad news is many strains of TB are becoming multidrug resistant and very hard to treat. Treating TB means taking antibiotics for at least 6-9 months, depending on things like whether your TB is active or inactive (latent), your overall health, and your age.

BCG vaccine is used in countries where TB is more common, and if you remember, Claire was working on this in Morocco before she was kidnapped. But the BCG vaccine isn't recommended for general use in the US because it isn't very effective in adults. Researchers continue to work on developing a more effective vaccine, and Claire's group is put to the test in Risking the World.